1. Field of the Invention
This invention relates to a control system for a legged mobile robot, more particularly to such a system for enabling a biped walking robot to walk stably even over terrain with unexpected irregularities.
2. Description of the Prior Art
Among the techniques that have been developed for enabling stable locomotion by a legged mobile robot is one which calculates the walking pattern in real time (Legged Robots on Rough Terrain; Experiments in Adjusting Step Length, by Jessica Hodgins. IEEE, 1988). Such technique cannot easily be applied for the control of a robot with multiple degrees of freedom, however, because such a robot is limited to the use of a compact, light computer too small to handle the huge amount of processing required. There have also been developed techniques for enabling walking by a legged mobile robot in which a walking pattern calculated in advance is stored in the memory of the robot's onboard computer and only simple data processing is conducted during walking. An example of a system based on this concept is taught by Japanese Laid-Open Patent Publication No. 62(1987)-97,006.
While this latter mentioned technique makes it possible to control a robot with multiple degrees of freedom using a computer that is compact and light enough to be carried by the robot, it is not always able to cope with encountered walking conditions which differ from those anticipated. Moreover, precalculation of walking pattern for a rough terrain is extremely difficult.